/*
 * Copyright (C) 2017 Schürmann & Breitmoser GbR
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.sufficientlysecure.keychain.util;

import java.math.BigInteger;

/**
 * Primes for ElGamal
 */
public final class Primes {
    // taken from http://www.ietf.org/rfc/rfc3526.txt
    public static final String P1536 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA237327 FFFFFFFF FFFFFFFF";

    public static final String P2048 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
                    "15728E5A 8AACAA68 FFFFFFFF FFFFFFFF";

    public static final String P3072 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
                    "43DB5BFC E0FD108E 4B82D120 A93AD2CA FFFFFFFF FFFFFFFF";

    public static final String P4096 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34063199" +
                    "FFFFFFFF FFFFFFFF";

    public static final String P6144 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
                    "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD" +
                    "F8FF9406 AD9E530E E5DB382F 413001AE B06A53ED 9027D831" +
                    "179727B0 865A8918 DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B" +
                    "DB7F1447 E6CC254B 33205151 2BD7AF42 6FB8F401 378CD2BF" +
                    "5983CA01 C64B92EC F032EA15 D1721D03 F482D7CE 6E74FEF6" +
                    "D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F BEC7E8F3" +
                    "23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
                    "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328" +
                    "06A1D58B B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C" +
                    "DA56C9EC 2EF29632 387FE8D7 6E3C0468 043E8F66 3F4860EE" +
                    "12BF2D5B 0B7474D6 E694F91E 6DCC4024 FFFFFFFF FFFFFFFF";

    public static final String P8192 =
            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
                    "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD" +
                    "F8FF9406 AD9E530E E5DB382F 413001AE B06A53ED 9027D831" +
                    "179727B0 865A8918 DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B" +
                    "DB7F1447 E6CC254B 33205151 2BD7AF42 6FB8F401 378CD2BF" +
                    "5983CA01 C64B92EC F032EA15 D1721D03 F482D7CE 6E74FEF6" +
                    "D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F BEC7E8F3" +
                    "23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
                    "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328" +
                    "06A1D58B B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C" +
                    "DA56C9EC 2EF29632 387FE8D7 6E3C0468 043E8F66 3F4860EE" +
                    "12BF2D5B 0B7474D6 E694F91E 6DBE1159 74A3926F 12FEE5E4" +
                    "38777CB6 A932DF8C D8BEC4D0 73B931BA 3BC832B6 8D9DD300" +
                    "741FA7BF 8AFC47ED 2576F693 6BA42466 3AAB639C 5AE4F568" +
                    "3423B474 2BF1C978 238F16CB E39D652D E3FDB8BE FC848AD9" +
                    "22222E04 A4037C07 13EB57A8 1A23F0C7 3473FC64 6CEA306B" +
                    "4BCBC886 2F8385DD FA9D4B7F A2C087E8 79683303 ED5BDD3A" +
                    "062B3CF5 B3A278A6 6D2A13F8 3F44F82D DF310EE0 74AB6A36" +
                    "4597E899 A0255DC1 64F31CC5 0846851D F9AB4819 5DED7EA1" +
                    "B1D510BD 7EE74D73 FAF36BC3 1ECFA268 359046F4 EB879F92" +
                    "4009438B 481C6CD7 889A002E D5EE382B C9190DA6 FC026E47" +
                    "9558E447 5677E9AA 9E3050E2 765694DF C81F56E8 80B96E71" +
                    "60C980DD 98EDD3DF FFFFFFFF FFFFFFFF";

    public static BigInteger getBestPrime(int keySize) {
        String primeString;
        if (keySize >= (8192 + 6144) / 2) {
            primeString = P8192;
        } else if (keySize >= (6144 + 4096) / 2) {
            primeString = P6144;
        } else if (keySize >= (4096 + 3072) / 2) {
            primeString = P4096;
        } else if (keySize >= (3072 + 2048) / 2) {
            primeString = P3072;
        } else if (keySize >= (2048 + 1536) / 2) {
            primeString = P2048;
        } else {
            primeString = P1536;
        }

        return new BigInteger(primeString.replaceAll(" ", ""), 16);
    }
}
